2009/15 Scientific papers, Series Bhttps://hdl.handle.net/10195/381862024-03-28T20:55:41Z2024-03-28T20:55:41ZOn the drive dynamics of a 4WS-carWeiner, MartinTesař, Miroslavhttps://hdl.handle.net/10195/422522012-07-08T00:01:43Z2009-01-01T00:00:00ZOn the drive dynamics of a 4WS-car
Weiner, Martin; Tesař, Miroslav
In the article study of drive dynamics of a 4WS-car (Four-Wheel Steering) based on the one-track model is resumed. Attention was focused on three single problems. At solving equations both analytical and numerical techniques were applicated. To effect calculations and plot outputs the
programming language Matlab was used.
2009-01-01T00:00:00ZModeling of stress in the car half axleBucha, JozefTurza, Jozefhttps://hdl.handle.net/10195/422512012-07-08T00:01:52Z2009-01-01T00:00:00ZModeling of stress in the car half axle
Bucha, Jozef; Turza, Jozef
The article describes the procedure for stress determining in the parts of car axle. It is designed and described model, where used modern programs and methods of calculation, which allows monitoring the size and distribution of stress in the components of the vehicle axle when the
vehicle ride through road bumps with different speeds. Road unevenness is generated according to ISO 8608, allowing easy quantification of quality of roads. The proposed model is universal. It can be used in other mechanical engineering fields.
2009-01-01T00:00:00ZExperimental measurement and simulation of harmonic frequency incurred from Czech railway networkRajský, FrantišekVejvodová, Evahttps://hdl.handle.net/10195/422502012-07-08T00:01:43Z2009-01-01T00:00:00ZExperimental measurement and simulation of harmonic frequency incurred from Czech railway network
Rajský, František; Vejvodová, Eva
This paper deals with modeling and simulation of processes in the distribution network of electric energy. For the scope of this paper, the simulation means the simulation of quality of electric energy with the main focus on voltage and harmonic frequencies of current in distribution
network. The point of connection of distribution network to the traction network was chosen as the point where measurements were taken and simulation was done.
Introduction part deals with AC and DC traction network. Then the article discusses the problem of modeling of different parts of the distribution network and traction network, such as: overhead line, contact line, Filtration Compensation Equipment, twelve-pulse rectifier, three-phase
three-wire transformer, traction transformer and load of railway tractive stock. The mathematical model of each part was drawn-up leading in a complex model of DC traction network connected to the 22 kV distribution network and the complex model of the one-phase AC traction network to the
110 kV distribution network. Software Pspice was employed to obtain simulations of particular components. Results of those simulations were compared with experimental measurements which were taken at the railway
lap of traction current converter plant Hoštka – Mělník (for DC traction network) and at the railway lap of the traction sub-station Bohatice (for AC traction network). Based on comparision of measured and simulated data of AC and DC traction network it could be concluded that current harmonic frequencies take similar values, particular diferences are discussed in the paper. Another conclusion is that measeured and simulated data do not meet limits for harmonic frequencies of current given by standards PNE 33 3430 and ČSN IEC 61 000-3 -4. Limits for harmonic frequencies of voltage stated in the standard ČSN EN 50 160 ed.2 are not exceeded.
2009-01-01T00:00:00ZTransport system equilibriumSalava, DanielŠvadlenka, Liborhttps://hdl.handle.net/10195/422492013-01-21T01:16:14Z2009-01-01T00:00:00ZTransport system equilibrium
Salava, Daniel; Švadlenka, Libor
Equilibrium in transport system is problem integrating itself some important aspects.
Economical aspect by setting of transport system equilibrium is one of key parts of investigated problem. It means especially investigation of mutually related influence of macroeconomical and transport system each other. Other sight on equilibrium solves marketing problem of interaction of
market cathegories in transport, thus transport demand and supply. Of course, technical and traffic provision face of transport system for its efficiency has the same importance. It is necessary of course for its perfect function to hold also relevant and adequate capability of transport
infrastructure. This side of problem comprises thus spatial aspect, and that is why it is important to consider also possibilities of solution of interregional transportations equilibrium and next problem
solution in context of transport network equilibrium. Modelling of these partial problems is naturally based on relevant factors, which influence directly and importantly particular areas of equilibrium and consequently it is possible to reflect them by means of mathematical expression.
Problems of transport system equilibrium cannot be solved strictly in complex form, because there exist some various aspects of its solution. Economical viewpoint by setting of transport system equilibrium is one of parts of this problem, but important role for transport system efficiency
is put also on technical and operational capaticies of this system, which requires for its function necessary of course sufficient infrastructure as well. This contribution otherwise comprises in
previous text in general model form just possible solutions of system equilibrium from spatial viewpoint, thus reflects equilibrium solution of interregional or multiregional transportations, and
next problem solution in sense of equilibrium on transport network. Modelling of this partial problems naturally works on relevant factors, which influence directly and significantly particular areas of equilibrium and simultaneously it is possible to express them by mathematical methods. The main goal and focusion of this paper is identification of relation between
macroeconomical and transport system on basis of appropriately selected representative variables
and then mathematical modelling of them from viewpoint of their mutual equal - balance state. Mission of solution results is not only verification of assumptions of concrete interaction between both systems, but on the basis of gained results also assessment of transport mode subsystems role in sense of their contribution to macroeconomical system. By transport system equilibrium
modelling in relation to macroeconomical system, concrete data are applied from those final equilibrium model of both systems is derived including verification of its validity by means of relevant mathematical methods. Solution, detection and understanding to problem of relations between macroeconomical and transport system is created by appropriately selected representative variables of both systems
and choice of structure and kind of enter data, which are quartal data of real gross domestic product in fixed prices of 2000 year and of traffic volumes in personal kilometres and tonal kilometres of passenger and freight transport for particular transport modes. Identification of mutual
relation between selected variables of macroeconomical and transport system provides
correlational analysis of stochastical components of time series. Before it, adequate smoothing and adjusting of data must be processed with verification of validity of gained results from used
technique for smoothing. In cases, when correlation analysis confirms close dependences, regressional modelling is processed from viewpoint of mutual equilibrial state of both systems.
State of variable of one system can also impact other system with certain delay, and that is why the attention is devoted also to delayed correlations of mutually inverse dependences with various time shifts. Results of regressional modelling including models followed from delayed correlations are
veryfied by testing methods for examinations of regressional parametres and rate of explanation of reality by models. Mission of solution results is not only verifiation of assumptions of concrete interactions between both systems, but also assessment of role of partial transport modes to their support of economical system with additional ideas of causes.
2009-01-01T00:00:00Z